1. Field of the Invention
The invention pertains generally to marine autopilot controllers and more particularly to a digital controller for commanding a change in course heading from a set course and for displaying the heading error.
2. Decription of the Prior Art
Prior art controllers are analog devices in which step data from a gryocompass are applied to a compass repeater with a synchro or potentiometer which is manually positioned with respect to the repeater dial for heading selection to produce a proportional rudder control signal. In shipboard navigation systems it is desirable to provide an auxiliary autopilot controller for use in the case of failure of the main autopilot controller. A problem in designing a controller that would fit in the available space on an existing ship control console is the lack of space to install the necessary analog components. Further, such precision components are expensive and not cost effective for a controller that is to be used only in the case of failure of the main controller.
The present invention utilizes digital electronics components to fit in the available space on an existing ship control console. By utilizing digital electronics, precision accuracy can be obtained at minimal cost and with only moderate space requirements. The use of digital electronics facilitates provision of a digital display for displaying heading error in degrees and fractions of degrees. The operator does not select a heading to steer but selects the number of degrees heading change from a set heading to arrive at and maintain a new heading.